Responsive hydrogels which have the capability to respond to external stimuli, such as temperature, pH, photons, and antigens, have attracted attention because such hydrogels can serve as functional materials with potential applications in the areas of drug/gene delivery, microlenses and sensors. Light-responsive hydrogels are promising because the activation process via light can be remote and noninvasive. For example, thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels have been shown to possess light responsiveness for microfluidic applications when incorporating gold nanoparticles (AuNPs). The light response is realized by combining the reversible hydration-dehydration transition of NIPAAm and the plasmonic absorption band in the near-infrared (IR) region of AuNPs. However, the volumetric change for the AuNP-containing hydrogel does not seem to be significantly more than that of the conventional responsive PNIPAAm hydrogel, thus limiting the potential applications for the material as an actuator.